吸入一氧化氮联合反比通气治疗感染性急性呼吸窘迫综合征

Effect of combination of nitric oxide inhalation and inverse ratio ventilation in endotoxin-induced acute respiratory distress syndrome in sheep

目的 :观察吸入一氧化氮 (NO)联合反比通气 (IRV)对感染性急性呼吸窘迫综合征 (ARDS)羊血流动力学、肺气体交换和机械力学的影响。方法 :静脉注入小剂量内毒素诱导的羊感染性 ARDS模型 12只 ,随机均分为两组。 NO组吸入 4 0× 10 - 6 NO,复合组联合容量控制反比通气 (VC IRV)和吸入 4 0× 10 - 6 NO。通过肺动脉导管、动脉和混合静脉血气分析 ,测定基础、ARDS和治疗 30 m in后肺气体交换和血流动力学参数 ,记录相应时间点的气道峰压 (PIP)、平均气道压 (Pm)和内源性呼气末正压 (PEEPi)。结果 :NO组和复合组治疗期间平均肺动脉压较 ARDS时均显著降低 (P均 <0 .0 1) ,动脉血压和心排血量则无明显变化 ;治疗 30 m in后 ,两组均能明显提高 ARDS的 Pa O2 (P均 <0 .0 1) ,减少肺泡动脉氧分压差〔 P( A a) O2 〕和肺内分流 (Qs/ Qt,P均 <0 .0 1) ,复合组更为显著 (P均 <0 .0 5 ) ;NO组各监测时间点 PIP、Pm均无明显变化 ,复合组的 Pm较治疗前及NO组对应时间点高 (P均 <0 .0 5 ) ,PIP则低 (P均 <0 .0 5 )。复合组治疗时 ,PEEPi为 (2 .5± 0 .5 ) cm H2 O(1cm H2 O=0 .0 98k Pa)。结论 :吸入 NO复合 IRV可协同改善 ARDS肺氧合 ,不影响体循环。

Objective: To observe the effect of combination of nitric oxide (NO) inhalation and inverse ratio ventilation (IRV) on oxygenation and hemodynamics in endotoxininduced acute respiratory distress syndrome (ARDS) in sheep. Methods: Sheep ARDS model was induced by an intravenous infusion of low dose endotoxin, and then animals were randomly divided into two groups. ①NO group ( n =6), inhalation of 40×10 -6 nitric oxide. ②Combination group ( n =6), receiving mechanical ventilation with IRV (inspiratory toexpiratory ratio of 2∶1) and inhalation of 40×10 -6 NO. The dynamic changes in gas exchange and hemodynamics were measured with the aid of SwanGanz catheter and arterial blood gas analysis before and after the onset of, ARDS and 30 minutes after treatment. Results: The combination of IRV and 40×10 -6 NO inhalation rapidly reduced mean pulmonary arterial pressure (MPAP), increased PaO 2, decreased P (Aa) O 2, and Qs/Qt without inducing significant change in systemic hemodynamics, and it was a more effective method of correcting hypoxemia than inhalation of nitric oxide alone. NO inhalation did not change the airway pressure of the model, but the combined treatment resulted in reduction of peak inspiratory pressure and increase of mean airway pressure. Conclusion: The combined use of IRV and NO inhalation has an additive effect on improving oxygenation in endotoxininduced acute respiratory distress syndrome in sheep.